Fashion: Entrepreneur Heidi Miller of Laguna Beach has moved on since founding Frogen Yozurt in 1981. Now she has a chain of body-conscious clothing stores.

She was a member of the U.S. Gymnastics Federation in the late '70s and an international bodybuilding champion, placing sixth in the world championships in 1986.

The Laguna Beach resident became one of the first entrepreneurs to peddle nonfat frozen yogurt. Heidi's Frogen Yozurt, which she launched 15 years ago and sold in 1989 to Steve's Ice Cream, turned into a mammoth chain of more than 100 stores.

Now, at age 42, Miller has turned her attention to what goes on the body. She's opened a small chain of stores that specialize in body-conscious clothing, including swimwear, workout wear and sexy street wear.

Her "cute and catchy" name for this latest venture: Tight Assets.

"People see the name and crack up," Miller says. "You've got to have that gimmick."

Miller is putting the same drive and energy into Tight Assets that she put into gymnastics and weightlifting.

On this day, she is charging around her Tight Assets store in South Coast Plaza's Crystal Court in Costa Mesa attending to matters large and small. She chats with customers, makes phone calls to clothing company representatives and even changes a dead lightbulb in her storefront sign.

"Every time I go into a store a lightbulb has burned out," she says with a sigh.

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In 1991, Miller opened her first Tight Assets in Cabo San Lucas, Mexico.

"I have a house in Cabo and was looking for a way to write off [in taxes] going down there all the time," she says.

Miller says she initially didn't care if the store made money. Yet figure-conscious customers loved the slinky bodysuits and bikinis, and her entrepreneurial instincts took over.

"The store turned out to be a little moneymaker," Miller says.

Four years ago she opened the Crystal Court store and later added stores in MainPlace/Santa Ana and Palm Desert.

She buys the clothes for all of her stores, traveling to wholesale marts in New York, Florida and California and visiting fitness and fashion trade shows such as the sportswear expo sponsored by Action Sports Retailer. She seeks out exclusive lines, clothes that can't be found in department stores.

"I want to be unique," she says.

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Among her favorite finds: Go Public, a line of batik-print leotards and other bodywear. The spring collection featured a bodysuit printed with a leaf motif in a taupe- and cream-colored knit ($42).

"Bodywear is now street wear," Miller says. "Women who don't work out wear bodysuits. I wear them all the time."

Women who do work out like wearing bra tops, now available with or without padding, drawstring bike shorts and leggings. Miller carries leggings in six lengths and 10 to 12 colors. She has T-back padded bra tops by One Step Ahead ($32) with matching drawstring shorts ($28).

"The big thing [in exercise wear] is to show off your middle," says Miller, who works out almost daily at the Irvine Sports Club.

She seeks swimsuits in all shapes and sizes, including bikinis with mix-and-match bras and tops. Among the looks: A faux tan suede bikini with padded bra top and Brazilian-cut bottom ($76).

Her street wear is geared to those who like to show off the results of their workouts.

There are form-fitting black Lycra dresses with short flared skirts and built-in bra tops (including one with a lace-up bustier, $95) and batik-print sun dresses by Tropical Tantrum, such as a flowing tank style in purple and blue floral print ($110).

Except for a six-year stint as a sales rep in "the rag business," Miller has little fashion experience. She majored in nursing at Cal State Sacramento. She moved to Laguna Beach in 1981 to open her first yogurt shop in Irvine.

She hopes to open one or two Tight Assets a year, avoiding the wild growth of her frozen yogurt chain.

"Heidi's got too big for my partner and me to manage," she says.

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Miller is already busy, traveling to the marts, visiting all of the stores, including regular trips to Cabo, and even designing a line of leotards, leggings, T-shirts and pullovers embroidered with the Tight Assets logo.

"I've never been afraid of failing," Miller says. "If I had had an MBA, I would have failed. They teach the pitfalls. I didn't see them. I had blinders on."

Although she's sometimes found herself with "my back against the wall," she can walk through MainPlace and see two companies she founded--Heidi's and Tight Assets.